Fish migration and reproduction in urban environment — restoration of the Lososinka River as habitat for the Onega Lake salmon, Petrozavodsk

To enable natural spawning, new projects to construct fish passes are going on in most big rivers in Finland. In the Interreg project «Restoring salmon runs into Oulu and Lososinka Rivers» fish pass options were examined for rivers in Finland and in Russia. Oulujoki River, once a famous salmon river is totally constructed and only few reproduction sites are left in the main channels and in some tributaries. To create new reproduction area, the principle of spawning channels which are commonly constructed in Canada, was integrated in the planning of nature-like fish passes. To optimize the area and quality of reproduction habitats, flow and habitat 2D modeling was used. The Lososinka River in Petrozavodsk, capital of Karelian Republic is a small urban stream 25 km long. It is blocked by dams, but there is still existing an original stock of landlock Onega Lake salmon. In the project measures for enabling migration through three dams in the city centre area were proposed. There are excellent reproduction habitats above the dams. Because of the value of the river as a key element in the urban environment, the landscape values had to be considered.